1. Field of the Invention
The present invention relates to clay forming. More specifically the invention is a clay cutting tool configured to cut clay elements, e.g. strips and other shapes from a soft clay slab.
2. Description of the Related Art
Clay elements cut from a clay slab or the like are assembled to form various clay objects. The assembled clay objects may comprise cylindrical and rectilinear enclosures e.g. clay pots, boxes, cups, pitchers, etc. or various other clay objects such as plates, bowls etc. which all may be assembled from a plurality of clay elements cut from a clay slab and joined together at seams or joints.
The use of beveled edges to join clay elements is known and desirable. Beveled edges increase joint or seam surface area and this provides a stronger joint. When two clay elements are joined at a 90 degree corner using a perpendicular joint, (no bevel) the joint contact dimension is equal to the thickness of the clay slab. However, when the same two clay elements are joined at a 90 degree corner using a 45 degree bevel the joint contact dimension is equal to 1.414 times the thickness of the clay slab. The increased joint contact dimension provides a stronger joint.
Conventional clay forming methods use a first step to cut a clay element from a clay slab and a second step to bevel edges that will be joined to other clay elements. More specifically a clay element cut from the clay slab is cut with perpendicular edges such that a cross-section of the clay element has four 90 degree corners. Thereafter a beveling tool is used to bevel edges that will be used to join the clay element to other clay elements. A conventional beveling tool comprises a body, e.g. a wood block that supports a tensioned wire or the like at a desired beveling angle. The conventional beveling tool is advanced along a clay element parallel to a perpendicular edge thereof. During the advancing step, the tensioned wire intersects the perpendicular edge at a desired beveling angle and cuts clay from the perpendicular edge to form a beveled edge. While the beveling tool can be advanced parallel to a perpendicular edge of the clay element without a guide, a straight edge is usually used to guide movement of the beveling tool. Typically the straight edge is positioned parallel to the perpendicular edge being beveled at a setback distance, e.g. equal to the thickness of the clay element, and the beveling tool is held against the straight edge as it is advance along the perpendicular edge of the clay element.
One problem with conventional clay beveling tools is that each beveling tool is configured for only one beveling angle. Thus a user needs to buy a different beveling tool for each desired beveling angle. Another problem with conventional beveling tools is that commercially available clay beveling tools are limited to only three beveling angles 30, 45 and 60 degrees and this has forced some users to custom make clay beveling tools for beveling angles other than 30, 45 and 60 degrees.
Another problem with conventional clay beveling tools is the need to align a straight guide edge parallel to and setback from a perpendicular edge being beveled. The problem with this is that when the alignment of the straight guide edge is not perfect, the resulting beveled edge is imperfect and may not match with a beveled mating part and the mismatch may require reshaping of the joint or seam at an assembly step.
A further problem with conventional clay beveling tools is that they can only remove clay from an upward facing surface. More specifically conventional clay beveling tools cut bevel angle of 30, 45 and 60 degrees as measured from the upward facing surface of the clay slab. However, due to the nature of the joining process; this typically requires that an unfinished surface of the clay element face upward during the beveling step. Thus in most applications, a user is forced to turn the clay element over placing its finished surface face down on a support surface with its unfinished surface face up in order to bevel its edges as required for assembly. However by turning the clay element over for beveling may deform its overall shape and the shape of any decorative featured formed on the finished side. The deformations may lead to poor fit or may render the clay element unusable.
A further problem with conventional clay beveling tools is that they are difficult to use on narrow clay elements. For example, if a user wished to bevel the edges of a 1 inch wide clay element it would be difficult to support and hold a straight guide edge on an upward facing surface of the 1 inch wide clay element and additional steps may be required to support and hold the straight guide edge in place during the beveling step.
After beveling, beveled clay elements are assembly into a clay object and this is usually done while the clay elements are still moist. In cases where a beveled edge is not well formed, e.g. when they have been formed by a conventional beveling tool, a user may reshape the clay by hand or using tools to adjust the fit and shape of joints or seams. However as the clay dries any clay that was reshaped attempts to return to its original shape (known as clay memory) and this tends to distort the reshaped joints and seams. Similarly when an assembled clay object is fired in a kiln, the firing process may heat the clay object to a near molten temperature and the heating process may also cause the clay to move. The movement typically affects the integrity of poorly formed seams and joints which can be distorted into non-straight or meandering edges.